Understanding backtest results

[Forex Trader]

I'm using Interbank FX's trade platform to run backtests with Expert Advisors I'm writing in MQL II. I've created an advisor that generates huge gains when I test under the "OHLC points" model and huge losses when I test under the "Every 1 point" model. I'm testing on a 1-hour chart and I see that the trades under the "OHLC points" model occur only at minutes 00, 15, 30, and 59. I don't understand why this is if I am using a 1 hour chart.

Can someone please explain the difference between these two test models? It looks like the system has some underlying 15-minute data it is using, but then why the odd 59 minute trade times. Maybe when I run the advisor in real-time I need to set the rules to only trade on the quarter-hour to achieve my positive results, but maybe the model is completely different than what I am imagining.

Steve